First report on phytochemical investigation, antioxidant and antidiabetic activities of Helianthemum getulum

Abstract

A new flavonoid, 5,7,2',4',5'-pentahydroxyflavone 3-O-β-D-galactopyranoside (12) and twelve known derivatives: an aryltetralin-lignan (3), seven flavonoids (4-5, 7-10, 13) and four phenolic acids (1-2, 6, 11) have been isolated from the aerial parts of Helianthemum getulum Pomel. (Cistaceae family) an endemic species to the septentrional Sahara that is being studied for the first time. Structure elucidation of the isolated compounds was established by means of spectroscopic methods especially NMR and Mass Spectrometry. In vitro antioxidant (DPPH, ABTS, GOR and CUPRAC assays) and antidiabetic (micro-dilution method) activities of the crude extract, fractions and isolated compounds were performed. The new flavonol (12) and Compounds (2, 3, 7, 9) were found to be the most active, some of them exhibiting better activity than the antioxidant standards. Compounds 7, 9 and 3 showed higher α-glucosidase inhibitory activity compared to standard acarbose (IC₅₀= 2.70 ± 0.03 µM, 3.09 ± 0.03 µM, 37.28 ± 1.20 µM and 275.43 ± 1.59 µM, respectively).

Keywords: Antioxidant and Antidiabetic activities; Helianthemum getulum; Lignan; NMR; Phenolic compounds.